1. Technical Field
This invention relates to antenna assemblies and, more particularly, to an antenna assembly that provides improved performance for portable transceiver applications.
2. Description of the Prior Art
In cellular telephony there are transceivers that are carried on vehicles such as cars and planes, and there are transceivers that are hand-carried. Of course, the need for reliable communication exists with both types of equipment and the challenge, in particular, is to ensure that reliable communication can take place in cellular networks even at the boundaries of cells.
Efforts directed at improving communications in mobile telephones have previously been undertaken. By way of example, U.S. Pat. No. 5,181,043, which issued to G. N. Cooper on Jan. 19, 1993, describes an arrangement having a passive repeater for cellular telephones. In particular, this arrangement has an antenna which is attached to the window of an automobile and serves as a passive repeater for reradiating a radio transmission received from a portable telephone within the automobile to a cell site within a cellular system. Also, in U.S. Pat. No. 4,989,012 which issued to N. E. Martensson et al. on Jan. 29, 1991, signal transmission and reception in an automobile is improved through use of an antenna assembly which permits operation of a portable telephone either with an antenna attached to the portable telephone or an external antenna attached to the automobile. As described in the Martensson et al. patent, the second external antenna attaches to the portable telephone through a coaxial transmission line.
Although both of the above-described arrangements provide for improved communications for a portable telephone, both arrangements also require additional hardware in the form of additional antennas to achieve the desired improvement. Moreover, these arrangements are intended for use in, and with, automobiles to which the external antennas are necessarily attached.
A typical hand-held portable transceiver has additional constraints. For example, the permitted radiated power level of a portable telephone is only 0.6 watts, so efficient radiation of this power is essential. Yet, cumbersome antenna arrangements are not well tolerated by the user. The need exists, therefore, to do as well as possible with minimum antenna configurations.